The Ultimate Rotary Tool Attachment

$2,000.00

I used a CNC mill in college to prototype circuit boards. I decided to build my own to use now. It is also a kit available for sale.

The function of a 3-axis CNC mill is really quite simple; Precision movement and control in 3 dimensional axis. This design has a resolution of 4000 steps per inch (1/4000 inch). Extruded Aluminum T-Slot stock was chosen as the construction medium for it's rigidity, stability and ease of use. The lightweight aluminum construction allows for an easy to transport, erect, and store desktop rotary tool attachment. The rotary tool is used in conjunction with a flex-cable extension. The extension's pen like end made a smaller and more easily mounted cutting head. Different working heads can be used with this device. A hobby knife can be mounted to cut vinyl lettering. A high wattage laser diode with fiber optic shaft can be used for wood burning and for etching plastic and other materials. A plasma cutter could theoretically be used as well.

Due to a minute amount of lateral flex in the cutting head, the final results are affected by the speed in which the deck travels. This only effects heads that make a physical contact with the piece being worked. Slowing the deck's travel speed allows the head to cut with less friction, resulting in a more true cut. * The origin of the lateral flex is in the cross member and linear bearing of the Z axis. X axis is the length of the device. Y is the width. The aluminum T-Slot is very rigid against lateral forces, however when a twisting force is applied, the stock flexes. The two foot length of the cross member allows for too much flex. The flex of course is amplified as the length of the Z axis is increased. This slop can be calculated using geometry and trigonometry.

Deflection angle of Z axis: <Zd

Length of Z axis: Zl

Slop: S

S = Zl / Tan (90 - <Zd)

S = Zl / Cot <Zd